Do they leak oil?

I'm trying to track down an oil leak or maybe leaks. from what i can see, it looks like oil is just running down the side of the block from under the heads. Heads are dry; block is covered with oil??

 

Are the ends of the block where the heads meet the deck dry ?

 

There is no pressurized oil that travels between the block and heads. Even the gravity oil returns are on the high side, above the bores. The LAST thing I would expect to see a head gasket leak, especially on the outside of the block, is oil.

RACE ON!!!

 

I am using them and so is a buddy of mine with an LS1/LS6.

Currently, no problems with either of us. I did have a problem in the past with water leakage with Cometics but that was due to the deck surface of the heads not being real flat.

Steve

 

Seems like the oil is running down the middle part of the block on both sides. I did have a leak at the corners of the intake rails, so it's possible that the oil ran around the edge of the head gasket and just decided to drop down the block at that point. I just fixed the intake leak and cleaned everything up....so we'll see if it's still leaking there or some place else. Keeping my fingers crossed that the problem is solve, but i'm doubtful.

 

I doubt it would be the head gasket leaking.

I am using them with my 406 and am happy with them. They do sit slightly below the oil galley's rear rail, so there is an open gap between the head, block and the intakes rear rail. Make sure you get some ultra black down into that crevise or you may leak more oil.

I have reused them once, so far so good.

 

Yes, have been forcing silicone down into that crevas, but i've had oil blowing past the rails. I think that was due to too much crank case pressure, which i have resolved.

This last time i used the GM silicone which dries a little hard than the ultra black. After driving it around town for a couple of days now, it's much better than it was, but still leaking from somewhere. I had one drop fall from the starter bolt and 2 drops from just behind the pan. The pan is still bone dry. Gonna have to get under the car and see where it's coming from. It possible the crankcase pressure blew the seal on the oil pan gasket. errrrrrrrrr!

 

Ya know, it sounds to me like we've been in the SAME boat! I have been hunting an oil leak for months, with two different sets of head gaskets, lots of intake changes, and a lot of cussing.

I think I know the source now, at least partially. The valve covers! The AFR heads have a very shallow oil return along the bottom edge and the oil actually runs over the gasket, which makes for a tough spot to seal. I have tried all the trick gaskets. What needs to be done in my case is to have the valve covers flattened on a large sander as there are a few places where the weld has a lip, causing a perfect spot to leak.

It may be that simple, have you crawled under there and looked up on the back corners of the valve covers?

 

I couldn't find an MLS type head gasket in the width I needed for quench. So I ended up with Flatout .021 silicone coated copper. It was about $125 delivered to my door.

 

The following is a repost of a thread I started not long after I did a h/c job on my C5. It's strictly an FYI in that I used Cometics and had a problem with them. Realizing I had this issue on a C5, take it FWIW.

This is an anecdotal as well as informational post so take it for what it's worth. I wanted to share this with you guys as a heads-up and possibly help someone else avoid the same problem in the future.

Last Oct.-Nov., forum member and good buddy Wt99C5, (Al, as I like to call him ) helped me install a h/c package in my '02 which had 2917 miles on it at the time. What we thought was going to take a couple of weekends to finish up ended taking many more weeks, including pulling the heads 4 times before this problem was resolved. Needless to say, we got good at pulling the motor apart and reassembling and readjusting everything.

I'll say up front that the tuner I bought the package from, MMS, was not at fault here. In fact, Mike was quite helpful and just as interested as we were to track down the problem. The problem was the Cometic gaskets that I ordered with the package. Mike recommended these but had never experienced the leak I had with them.

Here's what we installed:

> 5.3 liter ported and polished cylinder heads, milled .030" to bump compression up to 11.3:1 with 2.08" Intake valves / 1.58" Exhaust valves and Rev 1116 Dual valve springs/Titanium retaners
> 229/229/112 MMS cam
> Comp Cam Chromoly hardened pushrods (.050" shorter than stock)
> RollMaster (Australia) True Roller Dual Timing Chain / Sprocket set
> ASP Underdrive pulley (I had to modify slightly to account for the timing set spacer thickness)
> Ported oil pump
> RP head studs (amazing quality and strength and fantastic when you need to remove heads again like we did)
> Cometic Multi-layer Steel (MLS) cylinder head gaskets (great quality but a big mistake ordering these)
> Ported and polished Throttle Body
> Crank seal and water pump gaskets

After the install, we discovered a leak at the front, outboard corner of the passenger head. Coolant would slowly ooze between the head and gasket after heat-cycling the engine.



We surmised that we had a faulty Cometic head gasket and replaced it with a new one a week or so later. No dice. The second one leaked exactly in the same spot as the first, which I had sent back to MMS for their analysis.

Mike emailed me back with his assesment. He told me to note that the stock metal gaskets use a sticky sealant around the cooling passages and that GM probably does this because they take note of what the aftermarket does and incorporate this into their assembly process. Mike said the Cometic gasket was out before GM's metal gaskets were and that they probably noticed that a lot of engine builders using the Cometics were using copper sealant spray to prevent leaking so they decided to use sealant on their metal gaskets as a matter of course. Mike recommended using K/W 1612-12 copper gasket spray on the entire surface of both sides of the gasket before putting it back on. The sealant flows during torqueing and fills any potential crevices. He felt this would very likely solve the problem. We tried the K/W sealant on the third go-round on the passenger head gasket and - it stopped the coolant leak. However, now I had an oil leak in the same exact spot. Strange, but true.



Al and I did some more extensive research and measurements and came up with some pretty conclusive results which indicate why the gasket was leaking. It explains how oil could have been leaking out of the gasket and why I hadn't been able to attain a seal in the same location for the past month using different, new gaskets and sealant.

1) The Cometic has a .090" land around it's perimeter that must be engaged by the edge of the head all the way around to contain fluids (pic below). The stock gasket seals a substantial distance from the edge so that where the edge of the head is has no bearing on the seal.



2) The Cometic does not isolate the oil return galleys where the pushrods protrude in the head from the rest of the gasket like the stock gasket does. This can allow oil to migrate throughout the recesses of the gasket. No problem if the perimeter is sealed but if any part of the perimeter is not sealed, oil or coolant can leak through that breach. You can actually trace a path where the oil can enter the valley areas of the Cometic between the high land areas and seep all the way down to the lower stud areas.

3) I measured .118" of gasket protruding beyond the edge of the passenger head (pic below). This is where it was leaking. The edge of the head was not engaging the .090" raised land that the Cometic depends on for a good seal. The driver-side head, on the other hand, appeared to be engaging that area on the gasket and it had no leaks.



4) Below is a pic showing the raised land used on the stock gasket to seal the head (in yellow), the raised perimeter land the Cometic uses superimposed over the stocker (in red) and the faint line (H arrow in blue pointing to it) where the stock head casting impresses on the gasket.



Based on the above, I concluded that it's a hit-or-miss proposition as to whether these heads (earlier 5.3 liter with the notch) will seal with the Cometics. The Cometic gasket depends on the inaccurate head casting and whether or not it extends far enough out to meet the perimeter land to attain a seal. On my driver's side I lucked out and it sealed. On the passenger side it appears the edge of the head was recessed just far enough back to not want to seal. So, the variations in the casting can affect whether or not the gasket will seal - we're talking 0.25% shrinkage (.040"/16") of the casting upon cooling when pulled out of the mold. The K&W sealant helped couldn't compensate for the mis-match between the head and gasket. I never applied the sealant to the driver-side head and it sealed perfectly because the head edge matches the Cometic's.

What bolsters this explanation is the Cometic gasket I sent back to MMS as faulty. Al and I didn't realize the significance of it until later in the process, but the impression the corner of the head made on that gasket was inside the perimeter land within the valley area allowing passage of the coolant. There wasn't proper engagement of the head on the gasket so it's no wonder I hadn't been able to get a seal at this corner. GM got it right with the stock gasket because they don't depend on the rough, inaccurate outer edge of the gasket for seal integrity. The above pic shows that the raised land is well within the confines of the primary pressure region the stud nuts put on the head. Plus GM uses sealant along the entire length of the raised land at a generous thickness.

The significance of my long-winded explanation above is that I believed we needed to go to another type of gasket if we were ever going to get them to seal - preferably one configured like the stocker. The one gotcha' is the little edge recess at the #5 and #6 cylinders on my 5.3L heads which create a seal problem for the '02 style of gasket.

We ended up using the composite, earlier style '97-'00 GM gasket which fixed the leak once and for all. We also used them on Al's heads when we subsequently did his MMS h/c install and they worked on his as well. We couldn't find the Felpro's for our app at the time and had to account for the notch in the heads. The composite gaskets met all our needs.

I'm not impuning Cometic gaskets here as many use them successfully in similar and much higher hp applications, namely big bore and FI motors. As I said, take it FWIW.

Many thanks to Al for the monumental help and patience. Thanks to MMS for responding with suggestions and crediting us for the gaskets.

Ed

 

Patches, thanks for the explanation. I was stuck using the Cometics because i couldn't find a thin enough gasket that would work on my application..other than the Cometic or the copper that George discribed. I heard nothing but good things about the Cometics, and after seeing how they were constructed, i was sold on their strength. However, the fit wasn't exactly perfect. Brodix endorsed the Cometics and told me that they had a gasket specially made for the Track 1s. However after i got the gaskets, i saw that all the cooling passages were .125 dia, and the Brodix instructions called for .375 passages between the cylinders. When i questioned both Brodix and Cometic, they pointed the finger at each other. Finally they got together and decided the gaskets MIGHT workas is. Frigg'n Cometic never offered to take the gaskets back, but instead asked me to modify the ones i had. Drilling thru those suckers is no easy task. Anyway, to my surprise, i dont seem to be loosing any coolant, and i'm not yet certain the oil is coming from the head gasket. But i may be experiencing the same thing you did. The oil appears to be just sheeting down the side of the block from under the head. however i did have other known leaks in the intake rails that could have contributed. I have since corrected those leaks which helped reduce the problem, but i still see some drops under the car. When i get some time, i'll crawl under and see if i can trace them. Otherwise i'm bringing it to a shop that can trace the leak with dye and go from there.

 

Dang Ralph, I feel bad, I suggested the Cometics too, maybe I got lucky, mine went on with the AFR heads, but I did re-torque them after one heat cycle.

Hope you get it whipped!

 

Patches - Really nice Pictures and work! I think I would get depressed and want to choke somebody after the second R&R

I've been a copper head gasket man for years - because of the quick change mentality. I used to only spray them down with Permatex red sealant and get to wrenching. My older block style is much more forgiving

 

Have them on my 97' stroker.............no issues with over 4K hard miles on it.
My understanding was Cometic were best used for aluminum heads on cast iron blocks to help with the dissimilar material shearing forces ...........I have a 6.0 iron block.

 

Well now that i've driven the car a bit, i can say that the front of the intake is sealed up good...dry as a bone.

BUT.......my leaks persist. Best i can tell is that its coming down the back of the block on both sides. Doesn't seem to be running down the length of the block anymore.....so maybe that was the leak from the front of the intake just following the edge of the head around the side. Nonetheless i still have a leak somewhere and dont think it's the back of the intake. This is the third installation of an intake on the this engine. When i removed the intake this last time, the rear was dry and seemed to be well sealed. It appears to be coming from the corner of the head & block on both sides and potentially coming from the very back of the block, like from the galley plugs or somewhere up there. Where ever it's coming from, it winds up on the back part of the pan rail, then dips off the lip of the pan, the starter bolts and also runs down the belhousing of the trany and dips off the front of the tranny pan. Total PITA. I think i'm just going to bring it to a shop and let them put dye in the oil.

Any other thoughts?

btw, it aint the sending unit or the fittings there. They are dry.

 

Quick update:

Put dye in the oil and traced back some of the oil leaks. It appears to me that oil is actually leaking out from under the head gasket. It looks like it starts about 2-3 inches down from the intake rail. I'm thinking that the forward & rear most head bolts that are usually submerged in oil are leaking past the head gasket. I called Cometic and they were no help....they want to see the gasket, duh.

Rather than pull the heads at this point..i might try putting some o-rings or sealer on the shank of these head bolts to prevent oil from running down the shank and out from under the head gasket. comtetic said they had no embosement around those bolts so i suppose as oil runs down the shank of the bolt, it can leak out from under the head gasket. Actually, i guess this could be true of all the bolts under the valve cover. What a PITA.

 

When you installed the head gaskets did you check to see if the brass rivets were coming in contact with either the deck or the head surface.
I just got a pair of gaskets in today and was noticing the rivets in the area you are talking about. There's a raised area that surrounds the entire deck area that I'd think would catch any oil that gets down the stud or bolt.

I've had awesome luck using the Cometics on my Buick. After taking the heads off, I was amazed I hadn't burnt the gaskets between cylinders. Both banks had polished the teflon off the gaskets between cylinders from movement and too much heat in those areas.

I also put 3 coats of spray copper on both sides before installing them. I know they say not to, but I'd rather the extra little insurance in case of either of the surfaces not being smooth enough.

 

Thanks Slo....but the rivets are clear and i can see all three of them. I have no other explanation for the oil coming out from onder the head at that point. However my major leak looks like it's coming from the rear freeze plug behind the cam. What fun